The present invention relates to an arrangement for the protection of tube sections of platen-like heat-transfer surfaces disposed in a gas conduit against wear by gases laden with solid particles.
Arrangements for preventing damages due to wear to ancillary heat-transfer surfaces are known from the German Publication "Braunkohle", issued Mar. 3, 1961, the article entitled "Feuerungstechnik und Warmewirtschaft/Verschlei.beta.probIemebeiStaubkesseln" (Firing Technology and Heat Economy/Wear Problems in Dust Vessels), pages 81-94, especially pages 88, 89
Damage due to wear occurs, among other places, on the outer bends of bent tubes or meandering strips that are more or less closely adjacent to the conduit walls. The availability of surface to the dust-laden gases in these regions leads to an increased velocity at these locations due to the varying pressure loss over the entire heat-transfer surface over which the gas flows. This leads to greater wear, since the velocity occurs to the third or fourth power in the wear rate, whereas the dust loading occurs only linearly. The deflectors disclosed in FIG. 14 on page 89 of the aforementioned article not only directly protect the bends of the tubes, but also provide a further protection in that they deflect the solid particles onto the masonry of the conduit wall.
The deflectors are preferably secured to the tubes.
As shown in the lower half of the aforementioned FIG. 14, elongated tubular portions of the heat-transfer surfaces are protected by angle irons, flat bars, and tubular half shells that are secured to the linear tubular portions themselves.
Not only with those deflectors that extend parallel to the conduit wall and are associated with the outer rounded end portions, but also with regard to the profiled strips that protect the individual tubes, in order to replace such protective devices the connection to the tubular portion in the conduit that is to be protected must be loosened, and after a new wear-protection element has been provided this connection must be reestablished.
It is therefore an object of the present invention to provide an arrangement of the aforementioned general type that facilitates the replacement of the wear-protection elements.